None of the route or waypoint functions of the DGPS was used during the passage up the small craft channel to help validate radar and visual information. These functions could have been of great assistance to the vessel in making the planned deviation to the southeast of the centre of the recommended channel near the position of buoy AD-38. For a vessel such as the CANADIAN EMPRESS, a deviation to the southeast of the centre of the recommended channel is necessary in order to avoid crossing over the 1.83 m (6-foot) depth contour that overlaps the centre of the channel at this position. There is no gyrocompass fitted on the CANADIAN EMPRESS; consequently, the radar display is not gyro-stabilized. This seriously compromises the potential of the radar for navigation in restricted waters because without gyro-stabilization, parallel indexing is less accurate. Course made good, as indicated on a DGPS, is only accurate when the vessel is making way and when all the components of the DGPS system (land-based and space-based equipment) are functioning adequately. Although the master thought that he had correctly pushed the man overboard button on the DGPS to mark the position of the incident, no position was recorded. The master declared that he possibly did not hold the man overboard button down long enough for the function to register. Two days after the incident, the master reported the occurrence position to the Coast Guard Radio Station as latitude 4524'17 N, longitude 07354'12 W (see Figure 1) but qualified this position as approximate due to the numerous tasks and distractions immediately after the incident. Both the master and mate had extensive experience in these waters, but they had never navigated in that area with water levels so low. The predetermined distances used successfully in the past by the master for passing up Lynch Channel and past buoy AD-38 have the vessel crossing the tip of a 1.83-m (6-foot) depth contour that overlaps the centre of the recommended channel, as seen in figures 1 and 2. In the past, with water levels consistently 0.9 m to 1.2 m (3 to 4 feet) above chart datum, this was not a problem. On this voyage, with the water level only 0.28 m (11 inches) above chart datum, the intended course brought the vessel in proximity to water depths of less than 2.10 m (6.9 feet). Once abeam the first point at the predetermined distance of 213 m (700 feet), the intended track would have to have been approximately 224 true in order to make the second point at the predetermined distance of 244 m (800 feet) (see Figure 2). A proper passage plan was not being executed by the navigation personnel, and the progress of the vessel was not being plotted on the chart. The vessel was being steered by DGPS and followed a path of 233 (DGPS), very nearly the 234 true that would follow the centre of the recommended channel. This would suggest that the vessel was in fact more to the northwest than the approximate position reported by the master. Scarcely 30 m (100 feet) to the northwest of the approximate position given by the master is the 1.83 m (6-foot) depth contour mentioned earlier. The only individual sounding within this depth contour is a 0.91-m (3-foot) sounding 61 m (200 feet) to the northwest of the centre of the recommended channel. While all other depths within this contour are not known precisely, it is known that depths are less than 1.83 m (6 feet) above chart datum. At the time of the incident, the CANADIAN EMPRESS was drawing 1.6 m (5 feet 3 inches) aft, and the keel coolers were exceeding the hull by approximately 0.05 m (2 inches). Given that the damaged keel coolers were covered with a clay-like substance and given the observation by a passenger of the muddied waters astern the CANADIAN EMPRESS subsequent to the rumbling sound heard throughout the ship, it may be concluded that the vessel made contact with the bottom. The Canadian Hydrographic Service later sounded the area around the position of the grounding as reported by the master, but no anomaly in depth was found. As illustrated in Figure 2, the vessel was most probably 61 m to 76 m (200 to 250 feet) to the northwest of the reported approximate position of the incident and thus inside the 1.83-m (6-foot) depth contour when contact was made with the bottom.Analysis None of the route or waypoint functions of the DGPS was used during the passage up the small craft channel to help validate radar and visual information. These functions could have been of great assistance to the vessel in making the planned deviation to the southeast of the centre of the recommended channel near the position of buoy AD-38. For a vessel such as the CANADIAN EMPRESS, a deviation to the southeast of the centre of the recommended channel is necessary in order to avoid crossing over the 1.83 m (6-foot) depth contour that overlaps the centre of the channel at this position. There is no gyrocompass fitted on the CANADIAN EMPRESS; consequently, the radar display is not gyro-stabilized. This seriously compromises the potential of the radar for navigation in restricted waters because without gyro-stabilization, parallel indexing is less accurate. Course made good, as indicated on a DGPS, is only accurate when the vessel is making way and when all the components of the DGPS system (land-based and space-based equipment) are functioning adequately. Although the master thought that he had correctly pushed the man overboard button on the DGPS to mark the position of the incident, no position was recorded. The master declared that he possibly did not hold the man overboard button down long enough for the function to register. Two days after the incident, the master reported the occurrence position to the Coast Guard Radio Station as latitude 4524'17 N, longitude 07354'12 W (see Figure 1) but qualified this position as approximate due to the numerous tasks and distractions immediately after the incident. Both the master and mate had extensive experience in these waters, but they had never navigated in that area with water levels so low. The predetermined distances used successfully in the past by the master for passing up Lynch Channel and past buoy AD-38 have the vessel crossing the tip of a 1.83-m (6-foot) depth contour that overlaps the centre of the recommended channel, as seen in figures 1 and 2. In the past, with water levels consistently 0.9 m to 1.2 m (3 to 4 feet) above chart datum, this was not a problem. On this voyage, with the water level only 0.28 m (11 inches) above chart datum, the intended course brought the vessel in proximity to water depths of less than 2.10 m (6.9 feet). Once abeam the first point at the predetermined distance of 213 m (700 feet), the intended track would have to have been approximately 224 true in order to make the second point at the predetermined distance of 244 m (800 feet) (see Figure 2). A proper passage plan was not being executed by the navigation personnel, and the progress of the vessel was not being plotted on the chart. The vessel was being steered by DGPS and followed a path of 233 (DGPS), very nearly the 234 true that would follow the centre of the recommended channel. This would suggest that the vessel was in fact more to the northwest than the approximate position reported by the master. Scarcely 30 m (100 feet) to the northwest of the approximate position given by the master is the 1.83 m (6-foot) depth contour mentioned earlier. The only individual sounding within this depth contour is a 0.91-m (3-foot) sounding 61 m (200 feet) to the northwest of the centre of the recommended channel. While all other depths within this contour are not known precisely, it is known that depths are less than 1.83 m (6 feet) above chart datum. At the time of the incident, the CANADIAN EMPRESS was drawing 1.6 m (5 feet 3 inches) aft, and the keel coolers were exceeding the hull by approximately 0.05 m (2 inches). Given that the damaged keel coolers were covered with a clay-like substance and given the observation by a passenger of the muddied waters astern the CANADIAN EMPRESS subsequent to the rumbling sound heard throughout the ship, it may be concluded that the vessel made contact with the bottom. The Canadian Hydrographic Service later sounded the area around the position of the grounding as reported by the master, but no anomaly in depth was found. As illustrated in Figure 2, the vessel was most probably 61 m to 76 m (200 to 250 feet) to the northwest of the reported approximate position of the incident and thus inside the 1.83-m (6-foot) depth contour when contact was made with the bottom. The water level on Lake Saint-Louis, although 0.28 m (11 inches) above chart datum, was exceptionally low, at 1.17 m (3 feet 10 inches) below the average water level for the same time of year. The owner had requested that buoys above Sainte-Anne-de-Bellevue be placed early to facilitate the voyage up the Ottawa River. The Canadian Coast Guard had agreed to the request, and buoys H-2, H-12 and H-22 were in position before the CANADIAN EMPRESS began her first voyage of the season up the Ottawa River. All other buoys above buoy AD-18 were not yet in place, and the leading lights at Madore Point had been removed in 1996. The vessel's progress along her intended track was not adequately monitored by regularly plotting positions on the chart. Key navigational aids, such as the DGPS route and waypoint features, were not used to their fullest potential to assist in monitoring the vessel's progress. The man overboard button on the DGPS was reportedly depressed at the time of the incident, but no position was recorded subsequent to this action. The navigation personnel reported the bottom contact to the Canadian Coast Guard two days after the incident. Shortly after the incident, the waters astern of the CANADIAN EMPRESS were observed to be muddied. When the damaged keel coolers were removed from the hull, they were found to be covered with a clay-like substance. Both starboard keel coolers were damaged beyond repair due to bottom contact.Findings The water level on Lake Saint-Louis, although 0.28 m (11 inches) above chart datum, was exceptionally low, at 1.17 m (3 feet 10 inches) below the average water level for the same time of year. The owner had requested that buoys above Sainte-Anne-de-Bellevue be placed early to facilitate the voyage up the Ottawa River. The Canadian Coast Guard had agreed to the request, and buoys H-2, H-12 and H-22 were in position before the CANADIAN EMPRESS began her first voyage of the season up the Ottawa River. All other buoys above buoy AD-18 were not yet in place, and the leading lights at Madore Point had been removed in 1996. The vessel's progress along her intended track was not adequately monitored by regularly plotting positions on the chart. Key navigational aids, such as the DGPS route and waypoint features, were not used to their fullest potential to assist in monitoring the vessel's progress. The man overboard button on the DGPS was reportedly depressed at the time of the incident, but no position was recorded subsequent to this action. The navigation personnel reported the bottom contact to the Canadian Coast Guard two days after the incident. Shortly after the incident, the waters astern of the CANADIAN EMPRESS were observed to be muddied. When the damaged keel coolers were removed from the hull, they were found to be covered with a clay-like substance. Both starboard keel coolers were damaged beyond repair due to bottom contact. The vessel came into contact with the bottom because the navigation instruments and the technique used by navigation personnel did not permit precise navigation in the restricted channel. The route and waypoint features of the DGPS were not used to help monitor the vessel's progress along her intended track. Also, the water level was unusually low, leaving little room for error. The elimination of the Madore Point range and the absence of buoy AD-38 contributed in reducing the situational awareness of the navigation team.Causes and Contributing Factors The vessel came into contact with the bottom because the navigation instruments and the technique used by navigation personnel did not permit precise navigation in the restricted channel. The route and waypoint features of the DGPS were not used to help monitor the vessel's progress along her intended track. Also, the water level was unusually low, leaving little room for error. The elimination of the Madore Point range and the absence of buoy AD-38 contributed in reducing the situational awareness of the navigation team. Safety Action Taken Canadian Hydrographic Service Subsequent to the occurrence, the Canadian Hydrographic Service conducted soundings in the area surrounding the reported position of bottom contact. No anomaly in charted depth was found. As a result of the investigation into the occurrence, the TSB became aware of a difference between charts 1410 and 1510 in the charted location of the 6-foot bathymetric contour line of the shoal patch marked by buoy AD-38. A Marine Safety Information Letter (MSI 02/99) was forwarded to the Canadian Hydrographic Service apprising them of this difference. The Canadian Hydrographic Service has since produced chart amendment patches for charts 1410 and 1510. These amendment patches should appear in Canadian Notices to Mariners by mid 2000. Safety Concerns Aids to navigation have been reduced in the past four to five years. In particular, there are fewer buoys, and leading lights in small craft channels have been discontinued. The option of equipping small vessels, particularly passenger vessels, with gyrocompasses may be a way of increasing the accuracy of navigation and hence contributing to their safer operation. Currently, the Navigating Appliances and Equipment Regulations do not require passenger vessels between 300 and 500 gross tons to have gyrocompasses fitted. The Board is therefore concerned that there is an inherent risk when transporting passengers on small vessels without the equipment to navigate precisely in restricted waters under all conditions.